Consequences of pig domestication for skeletal muscle growth and cellularity

Dynamics of myofiber differentiation/maturation in porcine skeletal muscle is associated with domestication, breeding and rearing conditions. This study was aimed to comparatively elucidate the age-dependent myosin heavy chain (MyHC) isoform expression and transition pattern in domestic and wild pig (WP) skeletal muscle from birth until adulthood. Domestic pigs (DPs) of Large White breed raised in conventional production system were compared with WPs reared in a large hunting enclosure. Muscle samples for immuno/enzyme histochemistry were taken from the longissimus dorsi muscle within 24 h postmortem at 24 to 48 h, 21 to 23 days, 7 months and~2 years postpartum. Based on the antibody reactivity to MyHCs (NCL-MHCs, A4.74, BF-F3) and succinate dehydrogenase activity, myofibers were classified into I, I/IIa, IIa, IIx and IIb types. In addition, foetal MyHC expression was determined with the use of F158.4C10 antibody. Maturation of the longissimus dorsi muscle in the WP was characterized by an accelerated transformation of the fast to slow MyHC during the first hours postpartum, followed by differentiation towards oxidative myofibers in which type I, IIa and IIx MyHCs predominated. In the DP, the transformation shifted towards glycolytic myofibers that expressed MyHC-IIb. The expression of foetal MyHC was higher in the DP than in the WP at 1 day of age, and the decline in the foetal MyHC during the first 3 weeks was more rapid in the WP than in the DP denoting an accelerated early postnatal muscle maturation in WP than DP piglets. All foetal MyHC-positive myofibers co-expressed IIa isoform, but not vice versa. The intense myofiber hypertrophy was evident from 3 weeks until 7 months of age. In this period, the myofiber crosssectional area increased up to 10-and 20-fold in the WP and the DP, respectively. In the DP, the hypertrophy of all myofiber types was more pronounced than in the WP, particularly the hypertrophy of IIx and IIb myofibers. To summarize, the comparison between growing DP with wild ancestors showed that genetic selection and rearing conditions lead to substantial changes in the direction and intensity of postnatal MyHC transformation as evidenced by different proportion of individual myofiber types and differences in their hypertrophic potential.

contrasting

confidence: 94%

“…Morphological and physiological properties of myofibers, a major constituent of skeletal muscle, may underlay the antagonism between growth performance and meat quality traits (Rehfeldt et al, 2008). Therefore, the aim of this study was to further elucidate the influence of domestication on the differentiation of myofiber types.…”

mentioning

confidence: 99%

Dynamics of myosin heavy chain isoform transition in the longissimus muscle of domestic and wild pigs during growth: a comparative study

Fazarinc

Vrecl

Škorjanc

et al. 2017

“…As a loss of fibres after weaning in carnitine-treated pigs seems very unlikely (Rehfeldt et al, 1987;Bé rard et al, 2011), the compensation in total fibre number is suggested to result from a different trajectory of the earlypostnatal increase in fibre number in control and carnitinesupplemented piglets. An early-postnatal increase in total fibre number in pig muscle has been reported to occur in ST muscle cross sections at the mid-belly level (Rehfeldt et al, 2000 and2008b;Bé rard et al, 2011) and can be attributed to two mechanisms. On the one hand, the prenatal formation of primary and secondary myofibres (Wigmore and Stickland, 1983;Lefaucheur et al, 1995) is followed by a third wave of myofibre hyperplasia after birth and gives rise to new fibres.…”

Section: Discussionmentioning

confidence: 99%

“…Although the majority of muscle fibres is formed prenatally in the pig (Wigmore and Stickland, 1983;Rehfeldt et al, 2000), a postnatal increase in total fibre number in the cross-section of m. semitendinosus (ST) and m. psoas major has been observed in domestic and wild pigs (Rehfeldt et al, 1987 and2008b;Bé rard et al, 2011). This increase could be associated with the early-postnatal appearance of a third generation of fibres (Mascarello et al, 1992;Lefaucheur et al, 1995) or elongation of existing short fibres (Bérard et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Effects of l-carnitine supplementation to suckling piglets on carcass and meat quality at market age

Lösel

Rehfeldt

2013

Self Cite

In a previous study, carnitine supplementation to piglets during the suckling period resulted in an increased total muscle fibre number at weaning in piglets of low birth weight. The objective of the present study was to investigate whether this effect is maintained until market age and whether this would attenuate the negative consequences of low birth weight on carcass and meat quality. Using a split-plot design with litter as block, sex as whole plot and treatment as subplot, the effects of earlypostnatal L-carnitine supplementation on female and castrated male piglets of low birth weight were investigated on a total of 56 German Landrace piglets from 14 litters. From days 7 to 27 of age piglets were orally supplemented once daily with 400 mg of L-carnitine dissolved in 1 ml of water or received an equal volume of water without carnitine. From weaning (day 28) until slaughter (day 166 of age) all pigs were fed standard diets. At weaning, carnitine-supplemented piglets had a twofold increased concentration of free carnitine ( P , 0.001) and a lower concentration of non-esterified fatty acids ( P , 0.05) in blood plasma indicating that carnitine became bioavailable and increased fatty acid utilization during the period of supplementation. Growth performance was not influenced by treatment in any growth period. Dual-energy X-ray absorptiometry revealed no differences in body composition between groups in weeks 12, 16 and 20 of age. LW at slaughter, carcass weight, measures of meat yield and fat accretion, as well as body composition by chemical analyses and dissection of primal cuts did not differ between treatments. No differences between control and carnitine-treated pigs in total fibre number ( P 5 0.85) and fibre cross-sectional area ( P 5 0.68) in m. semitendinosus (ST) measured at slaughter could be observed. The carnitine group tended to exhibit a smaller proportion of slow-twitch oxidative fibres ( P 5 0.08), a greater proportion of fast-twitch glycolytic fibres ( P 5 0.11), and increased specific lactate dehydrogenase activity ( P 5 0.09) in ST indicating a more glycolytic muscle metabolism. Compared with the controls, a lower pH 24 value was observed ( P 5 0.05) in ST muscle of carnitine-supplemented pigs, which -in castrates only -was associated with an increased drip loss ( P , 0.01). Meat quality traits in m. longissimus were not influenced by treatment. In conclusion, our hypothesis that early-postnatal carnitine supplementation to piglets of low birth weight permanently increases myofibre number and improves later carcass and meat quality could not be confirmed by this experiment.

“…Ruusunen and Puolanne (2004) and Rehfeldt et al (2008) compared growth and muscular properties of wild and domestic pigs (DP). Despite higher weight, muscles of DP exhibited lower numbers of myofibres and were less mature at birth, which was associated with a lower proliferation rate of derived myoblasts.…”

Section: Introductionmentioning

confidence: 99%

Advances in research on the prenatal development of skeletal muscle in animals in relation to the quality of muscle-based food. II – Genetic factors related to animal performance and advances in methodology

Rehfeldt

Pas

Wimmers

et al. 2011

Self Cite

Selective breeding is an effective tool to improve livestock. Several selection experiments have been conducted to study direct selection responses as well as correlated responses in traits of skeletal muscle growth and function. Moreover, comparisons of domestic with wild-type species and of extreme breeds provide information on the genetic background of the skeletal muscle phenotype. Structural muscular components that differed with increasing distance in lean growth or meat quality in mammals were found to be myofibre number, myofibre size, proportions of fibre types as well as the numbers and proportions of secondary and primary fibres. Furthermore, markers of satellite cell proliferation, metabolic enzyme activities, glycogen and fat contents, the expression of myosin heavy chain isoforms, of activated AMPKa and other proteins in skeletal muscle tissue and circulating IGF1 and IGF-binding proteins have been identified to be involved in selection responses observed in pigs, cattle and/or chicken. The use of molecular methods for selective breeding of fish has only recently been adopted in aquaculture and studies of the genetic basis of growth and flesh quality traits are scarce. Some of the molecular markers of muscle structure/metabolism in livestock have also been identified in fish, but so far no studies have linked them with selection response. Genome scans have been applied to identify genomic regions exhibiting quantitative trait loci that control traits of interest, for example, muscle structure and meat quality in pigs and growth rate in chicken. As another approach, polymorphisms in candidate genes reveal the relationship between genetic variation and target traits. Thus, in large-scale studies with pigs' associations of polymorphisms in the HMGA2, CA3, EPOR, NME1 and TTN genes with traits of carcass and meat quality were detected. Other studies revealed the significance of mutations in the IGF2 and RYR1 genes for carcass lean and muscle fibre traits in pigs. Mutations in the myostatin (MSTN) gene in fish were also examined. Advances in research of the genetic and environmental control of traits related to meat quality and growth have been made by the application of holistic 'omics' techniques that studied the whole muscle-specific genome, transcriptome and proteome in relation to muscle and meat traits, the development of new methods for muscle fibre typing and the adaptation of biophysical measures to develop parameters of muscle fibre traits as well as the application of in vitro studies. Finally, future research priorities in the field are defined.Keywords: farm animal, fish, skeletal muscle, animal performance, genetic effects ImplicationsSkeletal muscle development in different animal species has been an important topic of scientific research for many years.*Authoring on behalf of all members of the COST action 925: http://www. agrsci.dk/costaction925/index.html -E-mail: rehfeldt@fbn-dummerstorf.de 718The main aim of this review is to present recent knowledge on the genetic components of skele...